Securing device



pw Z, M A. c. CATHERALL.

SECURING DEVICE Filed July 20, 1938 Patented Apr. 29, 1941 UNITED STATES PATENT GFFICE Application July 20, 1938, Serial No. 220,405 In Great Britain March 23, 1938 2 Claims.

This invention relates to securing devices and has particular reference to devices designed to secure doors, windows and the like against rattling but is capable of application in other directions.

The underlying principle of the invention is the utilisation of permanent magnets co-operating with other permanent magnets or elements of permeable material such as iron or steel and in carrying the invention into practice I either provide a magnet element on both parts to be secured or alternatively I provide a magnet element on one of the parts to be secured and I attach a mild steel or other permeable element to the other part. Under both these conditions when the two parts to be secured are brought together they will be held firmly against accidental displacement but can be readily separated by the exercise of moderate force.

An important practical feature of the invention is the provision of the magnet element in a housing or carrying structure of non-magnetic material whereby the magnet can be readily attached in position the magnet itself being of small size. A further feature of the invention is the provision of mild steel pole-pieces for the magnet as by this means the magnetic flux is increased. Other features of the invention will be apparent from the particular description and claims hereinafter appearing.

In the accompanying drawing I have illustrated examples of the invention and the manner in which it can be carried into practice.

In this drawing Figure 1 is a sectional View on the line l-l of Figure 2, showing a magnet fitting for attachment to a door jamb; Figure 2 is a side elevation of said magnet fitting. Figure 3 is a section through a door in its shut position showing the magnet element and the co-operating plate or armature carried by the door. Figure i is a perspective view of one form of the magnet element. Figure 5 shows in sectional elevation the application of the invention to sliding windows. Figure 6 is a section through a special arrangement of magnet element and its housing designed to permit movement of the magnet element to accommodate itself to its cooperating plate or armature.

Referring to this drawing and particularly to Figures 1-4, the numeral I designates a housing, which preferably consists of a die casting of non-magnetic material, in which is housed a magnet element 2 which preferably consists of a permanent magnet 2a clamped between mild steel pole pieces or plates 3 as shown in Figure 4.

The housing I has flanges for attaching purposes, as illustrated.

In operation the housing l with its magnet in situ is attached by screws to a door jamb 4. On the door 5 a mild steel plate 6 which acts as an armature to the magnet is similarly fixed by screws.

In the position shown in Figure 3 the door is in its closed position with the armature plate 6 held firmly by the magnet element 2. Themagnetic attraction is such that the door will be held firmly closed against rattling or accidental displacement but can be opened by the exercise of reasonable force.

Referring to Figure 5, there islwthere shown the application of the invention to""s"liding windows. In this case the magnet element Z carried by its non-magnetic housing l is attached rigidly to the fixed window frame l, while a mild steel plate 8 is attached to the side of the sliding window 9. By this means the window can be held in any desired position but the magnetic attraction is here again such that by the exercise of folce the window can be raised and lowered at w1 In Figure 6 there is illustrated a special construction of magnet housing whereby the mag.- net element is permitted a certain amount of movement to enable it to adjust itself to its cooperating armature plate in cases where precise parallelism is lacking. In this case the magnet element 2, which embodies substantially the same elements as the magnetic element 2 above described, instead of being a press fit rigidly fixed in its die-cast housing l is loosely located therein and is retained in position by a non-magnetic retaining plate l0 against which it is forced by means of a spring ll of non-magnetic material. This spring may be given a domed formation or provided with a spring mounted ball or other device which will permit the magnet to move in all directions sufficiently to enable it to adjust itself to its armature plate.

The principle of the invention can be applied to many cases where two relatively movable elements have to be temporarily secured together.

What I claim and desire to secure by Letters Patent is:

1. A magnetic door holding device for retaining a door member in position against accidental displacement with respect to a frame member wherein one of said members has an armature plate thereon comprising a housing of non-magnetic material, a recess in said housing, a magnetic element housed with facility for limited movement in said recess, a shoulder on said magnetic element, a retaining plate of non-magnetic material attached to the front face of said housing and operating to retain said magnetic element in said recess, a spring of non-magnetic material tending to press said magnetic element against said retaining plate whereby said magnet' can rock sumciently to adjust itself to its co-operating armature plate and means on said housing for mounting the same on the other of said members.

2. A magnetic door holding device for retaining a door member in position against accidental displacement with respect to a frame member,

wherein one of said members has mounted thereon an armature plate, comprising a housing of non-magnetic material having a recess extending inwardly from one open end thereof, a magnetic element in said recess, and means on said housing for mounting said housing on the other of said members immediately opposite the armature with the open end of the housing towards said armature, said magnetic element comprising a permanent magnet sandwiched between mild steel pole pieces, the ends of said magnet and said pole pieces lying substantially ush with the open end of the housing.

ALFRED CYRIL CATHERALL. 

